The present invention is related to a pneumatic tool, and more particularly to an oil filling structure of pneumatic tool, which enables an operator to conveniently fill the lubricant into the cylinder of the pneumatic tool.
A conventional pneumatic tool is powered by high pressure air for driving the rotor in the cylinder to rotate. In order to prolong using life of the pneumatic tool, the cylinder and the rotor must be lubricated and cleaned. The conventional lubricating measure is that the lubricant is filled into an air conduit connected with the pneumatic tool. When the high pressure air enters the conduit, the lubricant is sent into the cylinder along the air way inside the pneumatic tool and then exhausted therefrom along with the high pressure air. Accordingly, the interior of the pneumatic tool can be lubricated and the dirt in the cylinder can be entrained away from the cylinder to clean the same.
When adding the lubricant, the connector of the conduit must be detached for filling in the lubricant. This is inconvenient. Furthermore, the air conduit is generally made of plastic material so that the lubricant is likely to attach to inner wall of the conduit. Accordingly, the lubricant can be hardly totally transferred into the cylinder and some of the lubricant is wasted. In addition, after a period of use, the lubricant attaching to inner wall of the conduit tends to clog the conduit.